From: "NeilBrown" <neilb@suse.de>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: "Christoph Hellwig" <hch@lst.de>,
jean-noel.cordenner@bull.net, linux-fsdevel@vger.kernel.org
Subject: Re: i_version changes
Date: Thu, 14 Feb 2008 08:19:19 +1100 (EST) [thread overview]
Message-ID: <43290.192.168.1.70.1202937559.squirrel@neil.brown.name> (raw)
In-Reply-To: <20080213202611.GM13462@fieldses.org>
On Thu, February 14, 2008 7:26 am, J. Bruce Fields wrote:
> It's not OK to update it only sometimes. If updates are made while nfsd
> isn't running, those needed to be reflected in the change attribute, so
> the changes aren't missed when nfsd comes back up.
For NFSD's needs, it is only necessary that changes in i_version that are
potentially visible over NFS actually be stored on disk.
You could come up with an interface where NFSD sets a flag when it reads
i_version, and changes to the file only change i_version if the flag is
set (at which point the flag is cleared).
This would give fully correct NFS semantics, and no overhead when NFS access
is not in use
This flag would need to be stored in stable storage too, so probably easiest
to make it the least significant bit of i_version.
Of course then the semantics of the new i_version are very different to
the old i_version, so maybe we need two fields in the inode....
NeilBrown
next prev parent reply other threads:[~2008-02-13 21:19 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-10 7:30 i_version changes Christoph Hellwig
2008-02-12 20:06 ` J. Bruce Fields
2008-02-13 9:25 ` Andreas Dilger
2008-02-13 12:52 ` Christoph Hellwig
2008-02-13 14:07 ` Trond Myklebust
2008-02-13 15:12 ` Andreas Dilger
2008-02-13 20:26 ` J. Bruce Fields
2008-02-13 21:19 ` NeilBrown [this message]
2008-02-13 21:32 ` Peter Staubach
2008-02-13 22:06 ` NeilBrown
2008-02-14 14:34 ` Peter Staubach
2008-02-14 8:40 ` Jean noel Cordenner
2008-02-14 14:38 ` Peter Staubach
2008-02-15 10:31 ` Jean noel Cordenner
2008-02-13 21:36 ` J. Bruce Fields
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